1. Field of the Disclosure
Exemplary embodiments relate to a display device.
2. Description of the Related Art
The importance of display devices has recently increased with the growth of multimedia. Various types of display devices such as liquid crystal displays (LCDs), plasma display panels (PDPs), field emission displays (FEDs), and organic light emitting devices have been put to practical use.
Among them, the LCD and the light emitting device have come into the spotlight as a next generation display device because of the advantages of the LCD and the light emitting device. The LCD has better visibility than a cathode-ray tube, has low average power consumption, and generates less heat. The light emitting device has fast response speed, for example, about 1 ms, has low average power consumption, and does not have a viewable angle problem because the light emitting device is a self emitting device.
Such a display device is driven based on one of a passive matrix method and an active matrix method using a thin film transistor. In the passive matrix method, anodes and cathodes are formed orthogonally, and a display device is driven by selecting predetermined lines. On the contrary, in the active matrix method, a thin film transistor is connected to each pixel electrode, and the display device is driven according to a voltage sustained by a capacitor connected to a gate electrode of the thin film transistor.
A display device includes a display unit for displaying images and a driver for driving the display unit. The driver includes a printed circuit board (PCB) including parts for generating various control signal and data signals. The driver also includes a driving integrated circuit for applying a signal to lines of a display panel.
The driver may be classified into a chip-on-glass (OCG) type, a tape carrier package (TCP) type, and a chip-on-film (COF) type according to a method of packaging the driving integrated circuit into a panel. Among them, the COF type is widely used for a small sized panel because the COF has a simple structure and can increase a ratio of a display area in a display panel.
In a display device including a COG type driver, a pad unit includes a display unit, a line connected to a driving chip, a driver, and a pad electrode disposed at one end of the line. The driver is disposed on the pad unit through an anisotropic conductive film (ACF).
A pad electrode and a driver may be formed by coating an ACF on the pad electrode and compressing the driver on the pad electrode. Since a pad electrode according to the related art generally has a rectangular shape or a square shape, the flow of the ACF at the corners of a pad electrode when the driver is compressed with the ACF. As a result, conductive balls of an ACF lump together.
Therefore, short occurs between pad electrodes, and the reliability of a display device is deteriorated.